Enforce unique recipe item positions per recipe

Add migration 0018 with unique indexes on recipe_ingredients and
recipe_steps (recipe_id, position), so a recipe can never hold two
ingredients or two steps at one position. The dinner detail read now
orders by position alone and drops its read-time duplicate check; a
database already holding a duplicate fails the migration.

Maestro task 75bb8cc1-fd30-4050-90d2-a1627a865b22

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

internal/db/recipes.sql.go

@@ -220,7 +220,7 @@ func (q *Queries) GetRecipeBySourceURL(ctx context.Context, sourceUrl string) (R
 const listRecipeIngredients = `-- name: ListRecipeIngredients :many
 SELECT id, recipe_id, position, raw_text, name, qty, unit, note, created_at, updated_at FROM recipe_ingredients
 WHERE recipe_id = ?
-ORDER BY position, id
+ORDER BY position
 `
 
 func (q *Queries) ListRecipeIngredients(ctx context.Context, recipeID string) ([]RecipeIngredient, error) {
@@ -260,7 +260,7 @@ func (q *Queries) ListRecipeIngredients(ctx context.Context, recipeID string) ([
 const listRecipeSteps = `-- name: ListRecipeSteps :many
 SELECT id, recipe_id, position, text, created_at, updated_at FROM recipe_steps
 WHERE recipe_id = ?
-ORDER BY position, id
+ORDER BY position
 `
 
 func (q *Queries) ListRecipeSteps(ctx context.Context, recipeID string) ([]RecipeStep, error) {

internal/dinners/detail.go

@@ -157,10 +157,7 @@ func readRecipe(ctx context.Context, q *db.Queries, recipeID string, d *Detail)
 	if err != nil {
 		return fmt.Errorf("ingredients: %w", err)
 	}
-	for i, ing := range ings {
-		if i > 0 && ing.Position == ings[i-1].Position {
-			return duplicatePosition("ingredient", ing.Position)
-		}
+	for _, ing := range ings {
 		d.Ingredients = append(d.Ingredients, Ingredient{
 			Name:    nullString(ing.Name),
 			Qty:     nullString(ing.Qty),
@@ -173,10 +170,7 @@ func readRecipe(ctx context.Context, q *db.Queries, recipeID string, d *Detail)
 	if err != nil {
 		return fmt.Errorf("steps: %w", err)
 	}
-	for i, step := range steps {
-		if i > 0 && step.Position == steps[i-1].Position {
-			return duplicatePosition("step", step.Position)
-		}
+	for _, step := range steps {
 		d.Steps = append(d.Steps, step.Text)
 	}
 	return nil
@@ -283,11 +277,3 @@ func browserHost(u *url.URL) bool {
 	}
 	return true
 }
-
-// duplicatePosition is the error for two recipe items of kind at position.
-// Position is the only record of recipe order, and the id that breaks the
-// tie says nothing about it, so a recipe with a duplicate is refused rather
-// than shown in an order nobody can trust.
-func duplicatePosition(kind string, position int64) error {
-	return fmt.Errorf("two %ss at position %d: recipe order is unknown", kind, position)
-}

internal/server/dinnerdetail_test.go

@@ -70,8 +70,8 @@ func TestGetDinnerGroundedSideQuest(t *testing.T) {
 	}
 	for _, stmt := range []string{
 		`UPDATE dinners SET status = 'quest_log', origin = 'side_quest', is_favorite = 1 WHERE id = ?`,
-		`UPDATE recipe_ingredients SET position = 1 - position WHERE recipe_id = (SELECT recipe_id FROM dinners WHERE id = ?)`,
-		`UPDATE recipe_steps SET position = 1 - position WHERE recipe_id = (SELECT recipe_id FROM dinners WHERE id = ?)`,
+		`UPDATE recipe_ingredients SET position = 9 - position WHERE recipe_id = (SELECT recipe_id FROM dinners WHERE id = ?)`,
+		`UPDATE recipe_steps SET position = 9 - position WHERE recipe_id = (SELECT recipe_id FROM dinners WHERE id = ?)`,
 	} {
 		if _, err := e.st.Writer.Exec(stmt, id); err != nil {
 			t.Fatal(err)
@@ -445,25 +445,3 @@ func TestGetDinnerWhyPickedIsCreatingSuggestion(t *testing.T) {
 		t.Errorf("why_picked = %v, want %q", got.WhyPicked, reason)
 	}
 }
-
-// TestGetDinnerDuplicatePositionFails: a recipe with two ingredients or two
-// steps at one position has no order anyone can trust, so its detail is a
-// 500 rather than the recipe in some order.
-func TestGetDinnerDuplicatePositionFails(t *testing.T) {
-	t.Parallel()
-	e := newDinnersEnv(t)
-	for _, table := range []string{"recipe_ingredients", "recipe_steps"} {
-		id := createDinner(t, e.h, `{"name":"Family chili `+table+`"}`)
-		if rec, _ := callDinners(t, e.h, http.MethodPost, dinnersPath+"/"+id+"/ground",
-			`{"manual":{"ingredients":["1 lb beef","1 can beans"],"steps":["Brown.","Simmer."],"minutes":240,"method":"crockpot"}}`); rec.Code != http.StatusOK {
-			t.Fatalf("POST ground = %d: %s", rec.Code, rec.Body)
-		}
-		if _, err := e.st.Writer.Exec(`UPDATE `+table+` SET position = 0 WHERE recipe_id = (SELECT recipe_id FROM dinners WHERE id = ?)`, id); err != nil {
-			t.Fatal(err)
-		}
-		rec, _ := callDinners(t, e.h, http.MethodGet, dinnersPath+"/"+id, "")
-		if rec.Code != http.StatusInternalServerError || strings.Contains(rec.Body.String(), "Simmer.") || strings.Contains(rec.Body.String(), "1 lb beef") {
-			t.Errorf("GET with duplicate %s positions = %d: %s, want 500 and no recipe", table, rec.Code, rec.Body)
-		}
-	}
-}

internal/store/migrate_test.go

@@ -176,8 +176,8 @@ func TestMigrateEmbeddedMigrations(t *testing.T) {
 	if err := Migrate(context.Background(), s.Writer, migrations.FS); err != nil {
 		t.Fatal(err)
 	}
-	if got := versions(migrationRows(t, s)); got != "0000_bootstrap,0001_init,0002_household_settings_updated_by,0003_jobs_status,0004_ai_provider_presets,0005_ai_provider_xai,0006_ai_runs_status,0007_recipe_grounding,0008_dinner_recipe_url,0009_dinner_grounding_error,0010_dinner_grounding_revision,0011_ground_dinner_job_revision,0012_suggestion_name,0013_week_plan_revision,0014_rotation_review_name,0015_google_reconnect_required,0016_shopping_list_untitled,0017_shopping_list_chat_send_unconfirmed" {
-		t.Errorf("versions = %q, want 0000_bootstrap,0001_init,0002_household_settings_updated_by,0003_jobs_status,0004_ai_provider_presets,0005_ai_provider_xai,0006_ai_runs_status,0007_recipe_grounding,0008_dinner_recipe_url,0009_dinner_grounding_error,0010_dinner_grounding_revision,0011_ground_dinner_job_revision,0012_suggestion_name,0013_week_plan_revision,0014_rotation_review_name,0015_google_reconnect_required,0016_shopping_list_untitled,0017_shopping_list_chat_send_unconfirmed", got)
+	if got := versions(migrationRows(t, s)); got != "0000_bootstrap,0001_init,0002_household_settings_updated_by,0003_jobs_status,0004_ai_provider_presets,0005_ai_provider_xai,0006_ai_runs_status,0007_recipe_grounding,0008_dinner_recipe_url,0009_dinner_grounding_error,0010_dinner_grounding_revision,0011_ground_dinner_job_revision,0012_suggestion_name,0013_week_plan_revision,0014_rotation_review_name,0015_google_reconnect_required,0016_shopping_list_untitled,0017_shopping_list_chat_send_unconfirmed,0018_recipe_item_position_unique" {
+		t.Errorf("versions = %q, want 0000_bootstrap,0001_init,0002_household_settings_updated_by,0003_jobs_status,0004_ai_provider_presets,0005_ai_provider_xai,0006_ai_runs_status,0007_recipe_grounding,0008_dinner_recipe_url,0009_dinner_grounding_error,0010_dinner_grounding_revision,0011_ground_dinner_job_revision,0012_suggestion_name,0013_week_plan_revision,0014_rotation_review_name,0015_google_reconnect_required,0016_shopping_list_untitled,0017_shopping_list_chat_send_unconfirmed,0018_recipe_item_position_unique", got)
 	}
 }
 
@@ -197,8 +197,8 @@ func TestMigrateBootstrapThenEmbeddedInitApplies(t *testing.T) {
 	if err := Migrate(ctx, s.Writer, migrations.FS); err != nil {
 		t.Fatal(err)
 	}
-	if got := versions(migrationRows(t, s)); got != "0000_bootstrap,0001_init,0002_household_settings_updated_by,0003_jobs_status,0004_ai_provider_presets,0005_ai_provider_xai,0006_ai_runs_status,0007_recipe_grounding,0008_dinner_recipe_url,0009_dinner_grounding_error,0010_dinner_grounding_revision,0011_ground_dinner_job_revision,0012_suggestion_name,0013_week_plan_revision,0014_rotation_review_name,0015_google_reconnect_required,0016_shopping_list_untitled,0017_shopping_list_chat_send_unconfirmed" {
-		t.Errorf("versions = %q, want 0000_bootstrap,0001_init,0002_household_settings_updated_by,0003_jobs_status,0004_ai_provider_presets,0005_ai_provider_xai,0006_ai_runs_status,0007_recipe_grounding,0008_dinner_recipe_url,0009_dinner_grounding_error,0010_dinner_grounding_revision,0011_ground_dinner_job_revision,0012_suggestion_name,0013_week_plan_revision,0014_rotation_review_name,0015_google_reconnect_required,0016_shopping_list_untitled,0017_shopping_list_chat_send_unconfirmed", got)
+	if got := versions(migrationRows(t, s)); got != "0000_bootstrap,0001_init,0002_household_settings_updated_by,0003_jobs_status,0004_ai_provider_presets,0005_ai_provider_xai,0006_ai_runs_status,0007_recipe_grounding,0008_dinner_recipe_url,0009_dinner_grounding_error,0010_dinner_grounding_revision,0011_ground_dinner_job_revision,0012_suggestion_name,0013_week_plan_revision,0014_rotation_review_name,0015_google_reconnect_required,0016_shopping_list_untitled,0017_shopping_list_chat_send_unconfirmed,0018_recipe_item_position_unique" {
+		t.Errorf("versions = %q, want 0000_bootstrap,0001_init,0002_household_settings_updated_by,0003_jobs_status,0004_ai_provider_presets,0005_ai_provider_xai,0006_ai_runs_status,0007_recipe_grounding,0008_dinner_recipe_url,0009_dinner_grounding_error,0010_dinner_grounding_revision,0011_ground_dinner_job_revision,0012_suggestion_name,0013_week_plan_revision,0014_rotation_review_name,0015_google_reconnect_required,0016_shopping_list_untitled,0017_shopping_list_chat_send_unconfirmed,0018_recipe_item_position_unique", got)
 	}
 	if !tableExists(t, s, "dinners") {
 		t.Error("table from 0001_init was not created")
@@ -922,3 +922,92 @@ func TestMigrateShoppingListChatSendUnconfirmed(t *testing.T) {
 		t.Errorf("shopping list after 0017 = %s, want %s", got, want)
 	}
 }
+
+// seedRecipeItems inserts two recipes, each with an ingredient and a step
+// at position 0, then the extra statements.
+func seedRecipeItems(t *testing.T, s *Store, extra ...string) {
+	t.Helper()
+	stmts := []string{
+		`INSERT INTO recipes (id, source_url, title, raw_jsonld, fetched_at, created_at, updated_at)
+			VALUES ('recipe-1', 'https://example.com/chili', 'Chili', '{}', 'f', 'c', 'u')`,
+		`INSERT INTO recipes (id, source_url, title, raw_jsonld, fetched_at, created_at, updated_at)
+			VALUES ('recipe-2', 'https://example.com/curry', 'Curry', '{}', 'f', 'c', 'u')`,
+		`INSERT INTO recipe_ingredients (id, recipe_id, position, raw_text, created_at, updated_at)
+			VALUES ('ing-1', 'recipe-1', 0, '1 onion', 'c', 'u'), ('ing-2', 'recipe-2', 0, '1 lime', 'c', 'u')`,
+		`INSERT INTO recipe_steps (id, recipe_id, position, text, created_at, updated_at)
+			VALUES ('step-1', 'recipe-1', 0, 'Chop.', 'c', 'u'), ('step-2', 'recipe-2', 0, 'Squeeze.', 'c', 'u')`,
+	}
+	for _, stmt := range append(stmts, extra...) {
+		if _, err := s.Writer.Exec(stmt); err != nil {
+			t.Fatalf("seed: %v", err)
+		}
+	}
+}
+
+// TestMigrateRecipeItemPositionUnique applies 0018 over two recipes with
+// items at the same position: each recipe keeps its items, and a second
+// ingredient or step at a position its recipe already uses is refused.
+func TestMigrateRecipeItemPositionUnique(t *testing.T) {
+	ctx := context.Background()
+	s := openTestStore(t)
+	migrateBefore(t, s, "0018")
+	seedRecipeItems(t, s)
+
+	if err := Migrate(ctx, s.Writer, migrations.FS); err != nil {
+		t.Fatal(err)
+	}
+
+	var got string
+	if err := s.Reader.QueryRowContext(ctx, `SELECT
+		(SELECT group_concat(id || '@' || recipe_id || ':' || position, ',') FROM (SELECT * FROM recipe_ingredients ORDER BY id)) || ' / ' ||
+		(SELECT group_concat(id || '@' || recipe_id || ':' || position, ',') FROM (SELECT * FROM recipe_steps ORDER BY id))`).Scan(&got); err != nil {
+		t.Fatal(err)
+	}
+	if want := "ing-1@recipe-1:0,ing-2@recipe-2:0 / step-1@recipe-1:0,step-2@recipe-2:0"; got != want {
+		t.Errorf("recipe items after 0018 = %s, want %s", got, want)
+	}
+
+	for _, tc := range []struct{ name, stmt string }{
+		{"second ingredient at a position", `INSERT INTO recipe_ingredients (id, recipe_id, position, raw_text, created_at, updated_at)
+			VALUES ('ing-3', 'recipe-1', 0, '2 onions', 'c', 'u')`},
+		{"second step at a position", `INSERT INTO recipe_steps (id, recipe_id, position, text, created_at, updated_at)
+			VALUES ('step-3', 'recipe-1', 0, 'Dice.', 'c', 'u')`},
+		{"ingredient moved onto another's position", `UPDATE recipe_ingredients SET recipe_id = 'recipe-1' WHERE id = 'ing-2'`},
+		{"step moved onto another's position", `UPDATE recipe_steps SET recipe_id = 'recipe-1' WHERE id = 'step-2'`},
+	} {
+		if _, err := s.Writer.Exec(tc.stmt); err == nil || !strings.Contains(err.Error(), "UNIQUE constraint failed") {
+			t.Errorf("%s: error %v, want UNIQUE constraint failed", tc.name, err)
+		}
+	}
+}
+
+// TestMigrateRecipeItemPositionUniqueRefusesDuplicate applies 0018 over a
+// recipe already holding two ingredients, or two steps, at one position:
+// its order is unknown, so the migration fails and is not recorded.
+func TestMigrateRecipeItemPositionUniqueRefusesDuplicate(t *testing.T) {
+	for _, tc := range []struct{ table, stmt string }{
+		{"recipe_ingredients", `INSERT INTO recipe_ingredients (id, recipe_id, position, raw_text, created_at, updated_at)
+			VALUES ('ing-3', 'recipe-1', 0, '2 onions', 'c', 'u')`},
+		{"recipe_steps", `INSERT INTO recipe_steps (id, recipe_id, position, text, created_at, updated_at)
+			VALUES ('step-3', 'recipe-1', 0, 'Dice.', 'c', 'u')`},
+	} {
+		t.Run(tc.table, func(t *testing.T) {
+			ctx := context.Background()
+			s := openTestStore(t)
+			migrateBefore(t, s, "0018")
+			seedRecipeItems(t, s, tc.stmt)
+
+			err := Migrate(ctx, s.Writer, migrations.FS)
+			if err == nil || !strings.Contains(err.Error(), "UNIQUE constraint failed: "+tc.table+".recipe_id, "+tc.table+".position") {
+				t.Fatalf("Migrate = %v, want the duplicate position refused", err)
+			}
+			var n int
+			if err := s.Reader.QueryRowContext(ctx, `SELECT count(*) FROM schema_migrations WHERE version = '0018_recipe_item_position_unique'`).Scan(&n); err != nil {
+				t.Fatal(err)
+			}
+			if n != 0 {
+				t.Error("0018 recorded as applied")
+			}
+		})
+	}
+}

internal/store/schema_test.go

@@ -408,6 +408,8 @@ func TestSchemaUniqueConstraintsRejectDuplicates(t *testing.T) {
 		{"notification_outbox", []string{"event_key", "channel"}},
 		{"schedule_runs", []string{"schedule", "period_key"}},
 		{"notification_prefs", []string{"event"}},
+		{"recipe_ingredients", []string{"recipe_id", "position"}},
+		{"recipe_steps", []string{"recipe_id", "position"}},
 	}
 	s := seededStore(t)
 	for _, c := range cases {
@@ -445,6 +447,8 @@ func TestSchemaCompositeUniqueAllowsPartialOverlap(t *testing.T) {
 		{"same plan_date, different dinner", "rotation_reviews", "plan_date", "dinners", map[string]any{"dinner_id": rowID("dinners", 1)}},
 		{"same event_key, different channel", "notification_outbox", "event_key", "", map[string]any{"channel": "chat"}},
 		{"same period_key, different schedule", "schedule_runs", "period_key", "", map[string]any{"schedule": "week_rollover"}},
+		{"same position, different recipe", "recipe_ingredients", "position", "recipes", map[string]any{"recipe_id": rowID("recipes", 1)}},
+		{"same position, different recipe", "recipe_steps", "position", "recipes", map[string]any{"recipe_id": rowID("recipes", 1)}},
 	}
 	s := seededStore(t)
 	for _, c := range cases {